private ParseGraphNode ParseNode()
{
string token = Read();
if ((token == "s") || (token == "a"))
{
Read("(");
List <ParseGraphNode> nodes = new List <ParseGraphNode>();
while (Peek() != ")")
{
nodes.Add(ParseNode());
}
Read(")");
if (token == "s")
{
return(new SeqNode(null, nodes));
}
else if (token == "a")
{
return(new AltNode(null, nodes, false));
}
}
else if ((token == "?") || (token == "*") || (token == "+"))
{
Read("(");
ParseGraphNode body = ParseNode();
Read(")");
return(new RepNode(null, body, Reps.ForName(token[0])));
}
else if (token == "&")
{
Read("(");
ParseGraphNode body = ParseNode();
Read(")");
return(new AndNode(null, body));
}
else if (token == "!")
{
Read("(");
ParseGraphNode body = ParseNode();
Read(")");
return(new NotNode(null, body));
}
else if (token == "r")
{
Read("(");
char min = TextEscape.Unquote(Read())[0];
char max = TextEscape.Unquote(Read())[0];
Read(")");
return(new CharNode(null, new CharRange(min, max)));
}
else if (token == "l")
{
Read("(");
string label = Read();
ParseGraphNode body = ParseNode();
Read(")");
return(new LabelNode(null, label, body));
}
else if (token == "t")
{
Read("(");
ParseGraphNode body = ParseNode();
Read(")");
return(new TokenNode(null, body));
}
else if (token == "o")
{
Read("(");
Dictionary <string, object> options = new Dictionary <string, object>();
while (Peek() == "(")
{
Read();
string optionName = Read();
object optionValue = ReadValue();
options[optionName] = optionValue;
Read(")");
}
ParseGraphNode body = ParseNode();
Read(")");
OptionsNode optionsNode = new OptionsNode(null, body);
foreach (string key in options.Keys)
{
switch (key)
{
case "buildTextNodes":
optionsNode.BuildTextNodes.Value = (bool)options[key];
break;
case "dropPrecedence":
optionsNode.DropPrecedence.Value = (bool)options[key];
break;
case "recursive":
{
if ((bool)options[key])
{
optionsNode.RecursionBehaviour.Value = RecursionBehaviour.Recursive;
}
else
{
optionsNode.RecursionBehaviour.Value = RecursionBehaviour.None;
}
} break;
case "leftRecursive":
optionsNode.RecursionBehaviour.Value = RecursionBehaviour.LeftRecursive;
break;
case "rightRecursive":
optionsNode.RecursionBehaviour.Value = RecursionBehaviour.RightRecursive;
break;
case "whitespace":
{
object value = options[key];
if (value == null)
{
optionsNode.Whitespace.Value = null;
}
else
{
optionsNode.Whitespace.Value = Pattern.PatternForType((Type)value);
}
} break;
case "exclude":
optionsNode.Exclude.Value = Pattern.PatternForType((Type)options[key]);
break;
}
}
return(optionsNode);
}
else if (token == "any")
{
return(new AnyNode(null));
}
else if ((token[0] >= '0') && (token[0] <= '9'))
{
return(new PatternNode(null, patterns[Convert.ToInt32(token)], false));
}
else if (token[0] == '\'')
{
string text = TextEscape.Unquote(token);
if (text.Length == 1)
{
return(new CharNode(null, text[0]));
}
else
{
return(new TextNode(null, text));
}
}
throw new Exception(token);
}